JP2009097656A - Vehicle behavior stabilization device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately stabilize a vehicle behavior by changing a gear ratio in a shorter time compared to normal traveling to promptly decelerate a vehicle, when detecting instability of the vehicle behavior and automatically changing the gear ratio. <P>SOLUTION: This vehicle behavior stabilization device is provided with an electric power steering controller 1 for detecting instability of the vehicle behavior or the degree of behavior instability; a prime mover controller 2 for controlling prime mover output in accordance with the state of a prime mover; and a transmission controller 3 for controlling transmission of the prime mover output from the prime mover controller 2 to wheels. The transmission controller 3 for changing a gear ratio performs change operation of the gear ratio in a shorter time compared to normal traveling when it is determined that the vehicle behavior is unstable based on detection results related to vehicle behavior instability by the power steering controller 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle behavior stabilization device, and in particular, detects vehicle behavior instability such as understeer and oversteer of a vehicle, and automatically performs reduction of a prime mover output by a prime mover controller and change of a gear ratio by a transmission controller. The present invention relates to a vehicle behavior stabilization device for stabilizing a vehicle behavior by decelerating the vehicle.

  As a conventional vehicle behavior stabilization device, vehicle behavior instability is detected, and the motor output is reduced by the prime mover controller and the gear ratio by the transmission controller is reduced to the low speed side (the drive wheel speed per revolution of the prime mover). There has been an apparatus that stabilizes vehicle behavior by automatically executing a change (hereinafter referred to as a shift down) and decelerating the vehicle (see, for example, Patent Document 1).

JP 2003-31465 A

  A general transmission controller determines the target gear ratio according to the vehicle speed, accelerator opening, shift lever position, etc., and always changes from the current gear ratio to the target gear ratio. The driver can instruct downshift or upshift by operating the shift lever. Here, FIG. 13 shows an example of a change over time in the gear ratio when downshifting is performed by the driver operating the shift lever. In FIG. 13, the gear ratio is gradually changed from the current gear ratio to the target gear ratio over a certain period of time (hereinafter referred to as “shift time”). In the transmission controller, the speed change time (or a parameter that affects the speed change time) is set in advance, and the speed ratio is gradually changed based on this time. The shift time is generally set with priority given to ensuring the ride comfort of the passenger, and is usually set to a time significantly longer than the shortest shift time that the speed change mechanism can withstand mechanically. .

  Under such circumstances, the conventional device as described in Patent Document 1 detects the instability of the vehicle behavior and automatically downshifts when the driver performs the downshift by operating the shift lever as described above. The gear ratio was changed based on the same shift time setting value (value set with priority given to passenger comfort). For this reason, there has been a problem that the deceleration of the vehicle is slow and the effect of stabilizing the vehicle behavior is small.

  The present invention has been made to solve such a problem, and when the vehicle behavior instability is detected and the gear ratio is automatically changed, the gear ratio is changed in a shorter time than in normal driving, and the vehicle is immediately An object of the present invention is to obtain a vehicle behavior stabilization device capable of accurately stabilizing the vehicle behavior by decelerating the vehicle behavior.

  The present invention includes vehicle behavior instability detection means for detecting vehicle behavior instability or a degree of behavior instability, prime mover control means for controlling a prime mover output according to a state of the prime mover, and the prime mover output from the prime mover control means. Transmission control means for controlling the transmission of the vehicle to the wheels, and the transmission control means changes the gear ratio, and the vehicle is unstable in behavior based on the detection result of the vehicle behavior instability detection means. When it is determined that there is a vehicle behavior stabilization device, the transmission control means performs the speed ratio changing operation in a shorter time than during normal driving.

  The present invention includes vehicle behavior instability detection means for detecting vehicle behavior instability or a degree of behavior instability, prime mover control means for controlling a prime mover output according to a state of the prime mover, and the prime mover output from the prime mover control means. Transmission control means for controlling the transmission of the vehicle to the wheels, and the transmission control means changes the gear ratio, and the vehicle is unstable in behavior based on the detection result of the vehicle behavior instability detection means. When it is determined that there is a vehicle behavior stabilization device, the transmission control means performs the speed ratio changing operation in a shorter time than during normal driving. When changing the ratio, the gear ratio is changed in a shorter time than during normal driving, and the vehicle is decelerated immediately, thereby accurately stabilizing the vehicle behavior. Can.

  Hereinafter, an embodiment of a vehicle behavior stabilization device according to the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a vehicle behavior stabilization device according to the first embodiment. Reference numeral 1 denotes an electric power steering controller (vehicle behavior instability detecting means in the present embodiment) that controls the electric power steering and detects whether the vehicle is traveling normally or unstable in behavior. Reference numeral 2 denotes a prime mover controller for controlling the prime mover output in accordance with the state of the prime mover, and reference numeral 3 denotes a transmission controller for controlling transmission of the prime mover output to the wheels. These controllers are connected to a communication bus such as CAN and can perform message communication with each other.

  Next, the operation of the vehicle behavior stabilization device according to the present embodiment will be described. In the vehicle behavior stabilization device according to the present embodiment, when the electric power steering controller 1 detects an unstable vehicle behavior (here, understeer), the prime mover controller 2 and the transmission controller 3 decelerate the vehicle. Control is performed. Details of each controller will be described below.

  Details of the electric power steering controller 1 will be described. FIG. 2 is a detailed configuration diagram of the electric power steering controller 1 according to the present embodiment. Here, a portion related to understeer detection is shown, and a portion related only to steering assist torque control is common and is omitted. In FIG. 2, the electric power steering controller 1 includes various sensors including a steering angle sensor 11, a vehicle speed sensor 12, a steering torque sensor 13, a motor current sensor 14 and a motor rotation speed sensor 15, and a reference road surface reaction force torque calculator 16. A calculation processing unit including an estimated road surface reaction force torque calculator 17 and an understeer determiner 18 is provided.

  The steering angle sensor 11, the vehicle speed sensor 12, the steering torque sensor 13, the motor current sensor 14, and the motor rotation speed sensor 15 are provided in association with a vehicle steering system (not shown) including an electric power steering device. A steering angle sensor 11 detects a steering angle θh of a vehicle handle (not shown), a vehicle speed sensor 12 detects a vehicle speed V of the vehicle, and a steering torque sensor 13 is applied to the handle by a driver of the vehicle. The steering torque Ts is detected. The motor current sensor 14 detects a motor current Imtr flowing in an electric power steering electric motor (not shown) for assisting the driver's steering force, and the motor rotation speed sensor 15 is a motor of the electric power steering electric motor. The rotational speed ωmtr is detected.

The steering angle θh from the steering angle sensor 11 and the vehicle speed V from the vehicle speed sensor 12 are input to the reference road surface reaction torque calculator 16.
The vehicle speed V from the vehicle speed sensor 12, the steering torque Ts from the steering torque sensor 13, the motor current Imtr from the motor current sensor 14, and the motor rotation speed ωmtr from the motor rotation speed sensor 15 are estimated road surface reaction force torque calculators. 17 is input.

The reference road surface reaction torque calculator 16 calculates a reference road surface reaction torque Talign_ref based on the steering angle θh and the vehicle speed V, and inputs it to the understeer determination unit 18.
The estimated road surface reaction force torque calculator 17 calculates an estimated road surface reaction force torque Talign_est based on the steering torque Ts, the motor current Imtr, the motor rotation speed ωmtr, and the vehicle speed V, and inputs the calculated road surface reaction force torque Talign_est to the understeer determination unit 18.
The road surface reaction force torque is torque that attempts to return the tire to the straight direction when the steering wheel is steered.

  The understeer determiner 18 determines whether the vehicle is understeer based on the reference road surface reaction torque Talign_ref from the reference road surface reaction torque calculator 16 and the estimated road surface reaction torque Talign_est from the estimated road surface reaction torque calculator 17. Determine whether or not.

  An operation flow of the electric power steering controller 1 is shown in FIG. The electric power steering controller 1 periodically repeats the operation flow of FIG. First, the steering angle sensor 11 detects the steering angle θh (step E1), the vehicle speed sensor 22 detects the vehicle speed V (step E2), the steering torque sensor 13 detects the steering torque Ts (step E3), and the motor current. The sensor 14 detects the motor current Imtr (step E4), and the motor rotation speed sensor 15 detects the motor rotation speed ωmtr (step E5).

  Next, the reference road surface reaction force torque calculator 16 calculates the reference road surface reaction force torque Talign_ref based on the steering angle θh and the vehicle speed V as shown in the following equation (1) (step E6).

However, in the equation (1), Kalign is a ratio of the road surface reaction force torque to the steering angle θh in a traveling region where the road surface reaction force torque is not saturated, and is a unique value for each vehicle.
Further, since the value of the ratio Kalign varies depending on the vehicle speed, it is obtained in advance as a table value corresponding to each vehicle speed and stored in a memory (not shown) of the electric power steering controller 1.

Next, the estimated road surface reaction force torque calculator 17 calculates the estimated road surface reaction force torque Talign_est based on the steering torque Ts, the motor current Imtr, the motor rotation speed ωmtr, and the vehicle speed V (step E7).
The specific calculation process of the estimated road surface reaction torque Talign_est is omitted here, but is well known, for example, as disclosed in Japanese Patent Nos. 3353770, 2003-312521, and 2005-324737. Techniques can be used.

  Next, the understeer determination unit 18 calculates an understeering degree US_Index as shown in the following equation (2) based on the deviation between the reference road surface reaction torque Talign_ref and the estimated road surface reaction torque Talign_est (Step E8).

  In addition, the understeer degree US_Index obtained from the equation (2) indicates that the larger the value, the stronger the understeer of the vehicle.

  Here, the relationship between the steering angle θh and the understeer state, the standard road surface reaction force torque Talign_ref, the road surface reaction force torque, and the yaw rate will be described with reference to the explanatory diagram of FIG.

  FIG. 4 shows the relationship between the reference yaw rate and the actual yaw rate when the steering angle θh is increased from zero in constant vehicle speed driving on a low friction coefficient road surface (see the upper row), the reference road surface reaction force torque Talign_ref, and It shows the relationship with the road surface reaction torque (see the lower part).

  In FIG. 4, when the steering angle θh is increased, the reference road surface reaction force torque Talign_ref and the reference yaw rate (see the solid line) increase linearly as the steering angle θh increases.

  On the other hand, the road surface reaction torque (see the two-dot chain line) saturates away from the value of the reference road surface reaction torque Talign_ref when the steering angle θh is greater than or equal to the first steering angle θh1, and both increase with the increase of the steering angle θh. Deviation between torques increases.

  When the steering angle θh further increases and becomes a region equal to or larger than the second steering angle θh2 (> θh1), the actual yaw rate (see the one-dot chain line) saturates away from the standard yaw rate value, and the steering angle θh increases. Deviation between both yaw rates increases. That is, as the steering angle θh increases, the degree of understeer US_Index increases and the understeer of the vehicle becomes stronger.

  The road surface reaction force torque saturation occurs earlier than the actual yaw rate saturation by “θh2−θh1”. This is because, for example, the well-known document “Nakashima et al., A Vehicle State Detection Method Aligned Torque Using”. EPS, 05AC-46, 2005 SAE ", etc., and the present invention uses this phenomenon to detect the degree of understeer. The road reaction force torque saturation mechanism is also described in paragraphs [0006] to [0009] of Patent Document 1 and will be omitted (the road surface reaction torque in this specification is described in Patent Document 1). Same as lining torque).

  The understeer determiner 18 determines whether or not the understeer is understeered by determining whether or not the understeer degree US_Index exceeds a predetermined threshold value Th_us (step E9). And it transmits to the transmission controller 3 via a communication bus (step E10, step E11), and this process is complete | finished.

  Next, details of the prime mover controller 2 will be described. Since the configuration of the prime mover controller 2 is general, it will be omitted. The operation flow of the prime mover controller 2 is shown in FIG. The prime mover controller 2 periodically repeats the operation flow of FIG. First, the understeer determination result transmitted from the electric power steering controller 1 is received (step G1). The determination result is confirmed (step G2), and if it is not understeer, normal processing (primary motor output control according to the accelerator pedal depression amount, prime mover state, etc.) is performed (step G3), and the current processing is terminated.

  On the other hand, if the result of determination in step G2 is understeer, the motor output is reduced to a predetermined value in order to decelerate the vehicle (step G4), and the current process is terminated.

  Next, details of the transmission controller 3 will be described. Since the configuration of the transmission controller 3 is general, a description thereof will be omitted. An operation flow of the transmission controller 3 is shown in FIG. The transmission controller 3 periodically repeats the operation flow of FIG. First, the understeer determination result transmitted from the electric power steering controller 1 is received (step T1). The determination result is confirmed (step T2), and if it is not understeer, a gear ratio and shift time setting process (step T3 to step 7) during normal running is performed. That is, the vehicle speed (step T3), the accelerator opening (step T4), and the shift lever position are detected (step T5), and based on these, for example, the gear ratio 2.3 corresponding to the first speed is changed to the gear ratio 0 corresponding to the fourth speed. .5 is set (step T6), and the shift time set value is determined to be 1.5 seconds for normal driving (step T7). Here, the speed change time set value is the time required for the speed change operation.

  On the other hand, when the vehicle is understeering, a vehicle speed reduction gear ratio and shift time setting process is performed (steps T8 to T9). That is, the gear ratio is determined to a predetermined value (for example, 2.3 corresponding to the first speed) (step T8), and the gear change time set value is determined to be 0.5 seconds for vehicle deceleration (step T9).

  It is assumed that at least one of the above target gear ratio value and normal driving time and vehicle deceleration speed setting value is stored in advance in a memory (not shown) of the transmission controller 3.

  The processing after step T7 when understeering is the same as the processing after step T9 when understeering, and the speed ratio is actually changed based on the speed ratio and speed setting value determined so far (step T10). ), And terminates the current process.

  As described above, the present embodiment includes a shift time set value for normal travel and a shift time set value for vehicle deceleration (a value shorter than the shift time set value for normal travel). The speed change time setting value for deceleration is used. Thus, as shown in FIG. 7, when the vehicle behavior is unstable (solid line), the gear ratio can be changed in a shorter time than during normal driving (dashed line). Since it can be accurately stabilized, the effect of stabilizing vehicle behavior is great.

  In the present embodiment, the shift time setting value is 1.5 seconds or 0.5 seconds, but the present invention is not limited to this, and it may be set to an optimal value based on the driving test result or the like, or It may be determined each time based on the state quantity.

Embodiment 2. FIG.
The configuration of the vehicle behavior stabilization device according to Embodiment 2 of the present invention is basically the same as that of Embodiment 1. However, in the present embodiment, as shown in FIG. 8, an understeer degree calculator 28 is provided instead of the understeer determiner 18 in the first embodiment. The electric power steering controller in the first embodiment described above outputs whether or not the vehicle behavior is unstable, but in this embodiment, outputs the degree of vehicle behavior instability. Further, the transmission controller in the first embodiment uses a predetermined shift time set value for when the vehicle behavior is unstable (for vehicle deceleration) when the vehicle behavior is unstable. In accordance with the degree of behavior instability, the shift time set value is determined each time. Details will be described below.

  Details of the electric power steering controller 1 according to the present embodiment will be described. FIG. 8 is a detailed configuration diagram of the electric power steering controller 1 in the present embodiment. In FIG. 8, various sensors including a steering angle sensor 11, a vehicle speed sensor 12, a steering torque sensor 13, a motor current sensor 14, and a motor rotation speed sensor 15, a reference road surface reaction force torque calculator 16, an estimated road surface reaction force torque calculator. 17 is the same as that in the first embodiment. As described above, in the present embodiment, an understeer degree calculator 28 is provided instead of the understeer determiner 18 in the first embodiment. The understeer determination unit 18 in the first embodiment calculates the understeer degree US_Index, determines whether the understeer degree US_Index exceeds a predetermined threshold Th_us, and outputs the result. The understeering degree calculator 28 in this embodiment calculates the understeering degree US_Index in the same manner as in the first embodiment, and outputs the calculation result as it is.

  FIG. 9 shows an operation flow of the electric power steering controller 1 according to the present embodiment. The electric power steering controller 1 periodically repeats the operation flow of FIG. Steps E1 to E7 are the same as those in the first embodiment, and thus description thereof is omitted here. In the present embodiment, after step E7, the understeering degree calculator 28 calculates the above equation (2) as in the first embodiment, based on the deviation between the reference road surface reaction torque Torig_ref and the estimated road surface reaction torque Torig_est. ) To calculate the understeering degree US_Index (step E28). Then, the understeer degree US_Index is transmitted to the prime mover controller 2 and the transmission controller 3 via the communication bus (step E29), and the current process is terminated.

  Next, details of the prime mover controller 2 will be described. The operation flow of the prime mover controller 2 is shown in FIG. The prime mover controller 2 periodically repeats the operation flow of FIG. First, the understeering degree US_Index transmitted from the electric power steering controller 1 is received (step G21). Next, it is determined whether or not the understeer degree US_Index exceeds a predetermined threshold value Th_us (step G22). If not, normal processing (motor output control according to the accelerator pedal depression amount, the state of the engine, etc.) ) (Step G23), and the current process is terminated.

  On the other hand, if the understeering degree US_Index exceeds a predetermined threshold Th_us in the determination in step G22, the motor output is reduced to a predetermined value in order to decelerate the vehicle (step G24), and the current process is terminated.

  Next, details of the transmission controller 3 will be described. An operation flow of the transmission controller 3 is shown in FIG. The transmission controller 3 periodically repeats the operation flow of FIG. First, the understeering degree US_Index transmitted from the electric power steering controller 1 is received (step T21). Next, it is determined whether or not the understeering degree US_Index exceeds a predetermined threshold value Th_us set in advance (step T22). If not, the gear ratio and shift time setting process during normal driving (step T23 to step 27) is performed. To implement. Steps T23 to T27 are the same as steps T3 to T7 in the first embodiment.

  On the other hand, when the understeering degree US_Index exceeds a predetermined threshold Th_us, a vehicle speed reduction gear ratio and shift time setting process is performed (step T28 to step T29). Specifically, first, the gear ratio is determined to be a predetermined value (for example, 2.3 corresponding to the first speed) (step T28), and then the shift time is set by map calculation according to the understeering degree US_Index. A value is determined (step T29). Here, for example, as shown in FIG. 12, the map is set so that the shift time setting value becomes shorter as the understeering degree US_Index is larger, and this map is stored in the memory of the transmission controller 3. .

  The processing after step T27 when the understeering degree US_Index does not exceed the predetermined threshold Th_us and the processing after step T29 when the understeering degree US_Index exceeds the predetermined threshold Th_us are the same. Based on the set value, the gear ratio is actually changed (step T210), and the current process is terminated.

  Thus, in the present embodiment, the shift time set value is determined according to the degree of instability of the behavior of the vehicle. For this reason, when the degree of vehicle behavior instability is small, the vehicle behavior can be stabilized without greatly deteriorating the ride comfort of the passenger, and the shift time set value is shortened only when the degree of vehicle behavior instability is large. Therefore, it is possible to accurately stabilize the vehicle behavior while considering the ride comfort of the passenger.

  In this embodiment, the shift time set value is determined by map calculation. However, the present invention is not limited to this, and a predetermined calculation formula for obtaining the shift time set value from the understeer degree US_Index is used. Also good.

  In the first and second embodiments, when the vehicle behavior is unstable, the prime mover output is reduced to a predetermined value and the gear ratio is changed to a predetermined value. For example, it may be determined each time according to the degree of instability of the vehicle behavior and other state quantities.

  In the first and second embodiments, the parameter for gradually changing the gear ratio is referred to as “shift time”, but any other parameter that affects the shift time may be used. For example, the target gear ratio When a low-pass filter is applied to this calculation, the time constant may be reduced when the vehicle behavior is unstable.

  In the first and second embodiments, an example of CVT (Continuously Variable Transmission) in which the gear ratio continuously changes has been described. However, a stepped transmission may be used. The time for changing from the non-engaged state to the engaged state may be changed. The prime mover control means may be either an internal combustion engine or an electric motor. If the prime mover is an internal combustion engine, the supply air amount or the fuel amount is suppressed, the ignition timing is changed, or the prime mover is an electric motor. The output is reduced by suppressing the current supplied to the motor.

  In the first and second embodiments, in order to detect understeer, an estimated road reaction torque and a reference road reaction torque are calculated, and the absolute value of the deviation is set as an understeer degree US_Index, which exceeds a predetermined value. However, the understeer determination method based on the estimated road reaction torque is not limited to this. For example, the estimated road reaction torque calculated in the same manner as in the present embodiment is differentiated. "Estimated road surface reaction force torque change rate Talign_rate_est" is calculated, and "Road surface reaction torque standard change rate Talign_rate_ref" is calculated by the following equation (3), and the following equation (4) is set as the understeering degree US_Index. As in the present embodiment, understeer can be detected based on the road surface reaction torque saturation phenomenon (when the road surface reaction torque is saturated). , Since the difference occurs in the road surface reaction torque norms change rate Talign_rate_ref estimated road surface reaction torque change rate Talign_rate_est). With this method, the steering angle sensor 11 shown in FIGS. 2 and 8 is unnecessary, and the manufacturing cost of the understeer suppressing device can be reduced.

  However, in Equation (3), ωh is a steering wheel steering speed (motor rotation speed ωmtr multiplied by a gear ratio), and V and Kalign are the same as the above formula (1).

  Further, in the first and second embodiments, the example in which understeer is detected based on the information of the electric power steering controller has been shown, but the vehicle behavior instability detection method may be another known method, for example, As disclosed in Japanese Patent Laid-Open No. 6-99800, a method for detecting understeer or oversteer by comparing a reference yaw rate calculated from a steering wheel angle and a vehicle speed and an actual yaw rate detected by a yaw rate sensor is known.

  In the present embodiment, the vehicle behavior instability is detected, and both the reduction of the motor output by the prime mover controller and the shift down by the transmission controller are performed, but only the shift down by the transmission controller is performed. You may do it. Further, depending on the output state of the prime mover, the vehicle driving speed may be reduced by shifting up instead of downshifting, thereby decelerating the vehicle.

It is a block diagram of the vehicle behavior stabilization apparatus which concerns on Embodiment 1 of this invention. It is a block diagram of the electric power steering controller which concerns on Embodiment 1 of this invention. It is an operation | movement flowchart of the electric power steering controller which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the relationship between the steering angle by this Embodiment 1, a reference | standard road surface reaction torque, a road surface reaction torque, a yaw rate, and an understeer. It is an operation | movement flowchart of the motor | power_engine controller which concerns on Embodiment 1 of this invention. It is an operation | movement flowchart of the transmission controller which concerns on Embodiment 1 of this invention. It is a gear ratio transition diagram in the transmission controller according to Embodiment 1 of the present invention. It is a block diagram of the electric power steering controller which concerns on Embodiment 2 of this invention. It is an operation | movement flowchart of the electric power steering controller which concerns on Embodiment 2 of this invention. It is an operation | movement flowchart of the motor | power_engine controller which concerns on Embodiment 2 of this invention. It is an operation | movement flowchart of the transmission controller which concerns on Embodiment 2 of this invention. It is a shift time calculation map of the transmission controller which concerns on Embodiment 2 of this invention. It is gear ratio transition explanatory drawing for demonstrating the subject which this invention tends to solve.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Electric power steering controller, 2 Motor controller, 3 Transmission controller, 11 Steering angle sensor, 12 Vehicle speed sensor, 13 Steering torque sensor, 14 Motor current sensor, 15 Motor rotational speed sensor, 16 Reference road surface reaction force torque calculator , 17 Estimated road surface reaction force torque calculator, 18 understeer determiner, 28 understeer degree calculator.

Claims (5)

Vehicle behavior instability detection means for detecting vehicle behavior instability or behavior instability, and
Prime mover control means for controlling the prime mover output according to the state of the prime mover;
Transmission control means for controlling transmission of the prime mover output from the prime mover control means to wheels, and
The transmission control means is for changing a gear ratio,
When it is determined from the detection result of the vehicle behavior instability detection means that the vehicle is unstable in behavior, the transmission control means performs the speed ratio changing operation in a shorter time than during normal driving. A vehicle behavior stabilization device. The transmission control means sets the shift time setting value, which is a set time to be applied to the speed ratio changing operation while changing the speed ratio.
The shift time setting value includes a first shift time setting value used during normal driving and a second shift time setting value shorter than the first shift time setting value used when the vehicle behavior is unstable. The vehicle according to claim 1, wherein which of the first shift time set value and the second shift time set value is used is determined according to a detection result of the vehicle behavior instability detection means. Behavior stabilization device. The vehicle behavior instability detection means detects the behavior instability level of the vehicle,
When the vehicle behavior instability exceeds a predetermined value,
The vehicle behavior stabilization device according to claim 1 or 2, wherein the transmission control means determines the shift time set value based on a degree of behavioral instability of the vehicle.   4. The vehicle behavior stabilization apparatus according to claim 3, wherein the transmission control means shortens the speed change time of the speed ratio as the degree of behavior instability of the vehicle increases. The vehicle behavior instability detecting means is
Vehicle speed detection means for detecting the vehicle speed;
Steering torque detecting means for detecting the steering torque of the driver;
An electric motor that assists the steering force of the driver;
Motor current detecting means for detecting a motor current of the electric motor;
Motor speed detecting means for detecting the rotational speed of the electric motor;
An estimated road surface reaction torque calculating means for calculating an estimated road surface reaction torque based on the vehicle speed, the steering torque, the motor current, and the rotational speed;
The vehicle behavior stabilization device according to any one of claims 1 to 4, wherein a vehicle behavior instability or a behavior instability level is detected based on an output of the estimated road surface reaction force torque calculation means. .

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